Hazards of Space Travel

• Astronauts face eight hazards during space travel.
• NASA studies these hazards to overcome the challenges of sending humans to the space station, the Moon, Mars, and other destinations.

Weightlessness or Microgravity

• Weight is the attraction between Earth and an object, also known as gravity.
• In space, gravity is very weak, resulting in weightlessness or microgravity.
• Astronauts cannot drink from a glass in space because liquid will not fall into their mouths.
• Anything not fastened inside a spacecraft will float, and astronauts float around too.
• Spacewalking astronauts wear space suits hooked up to the spacecraft.
• Weightlessness can cause dizziness, bone and muscle loss, and vision issues.

Radiation from Space (Cosmic Radiation)

• Earth's magnetic field and atmosphere shield us from most space radiation.
• Everyone on Earth is exposed to low levels of radiation daily.
• Astronauts in space are exposed to varied and increased radiation levels.
• Three main sources contribute to space radiation: particles trapped in Earth's magnetic field, solar energetic particles from the Sun, and galactic cosmic rays.
• Space radiation is invisible, stealthy, and a hazardous aspect of spaceflight.
• Spacecraft walls usually protect astronauts from harmful rays.
• Astronauts wear specially designed spacesuits during spacewalks for protection.
• Beyond Low Earth Orbit, radiation poses a significant risk for radiation sickness, cancer, central nervous system effects, and degenerative diseases.

Temperature and Pressure

• Earth's temperature ranges from 16 to 27 degrees Celsius.
• Space temperatures are not in the right range for humans.
• Spacecraft moving closer to the sun become very hot, while those moving further become very cold.
• Temperature inside a spacecraft must be carefully controlled.

Food

• Early space travelers ate special food squeezed from containers.
• Today, astronauts can bring selected regular food into space due to technology advancements.

Oxygen

• Humans need oxygen to breathe, which is not available in space.
• Astronauts must bring a supply of oxygen with them when traveling to space.
• Longer stays in space require more oxygen.

Isolation & Confinement

• Expedition crews are carefully selected, trained, and supported for 6-12 month space station missions.
• Moon or Mars mission crews undergo more intensive assessment due to longer travel in isolated environments.
• NASA studies people in isolated environments.
• Astronauts keep journals to express frustrations, providing researchers with insights into behavioral problems.
• Virtual reality is being researched to simulate relaxing environments, improving mood.
• Relevant activities, like language or medical skill learning, can ward off depression and boost morale.
• Space gardens can provide behavioral health benefits, fresh food, and air purification.

Distance from Earth

• The space station orbits 240 miles above Earth.
• The Moon is 1,000 times farther than the space station.
• Mars averages 140 million miles from Earth, with a communication delay of up to 20 minutes one-way.
• Mars astronauts must solve problems independently due to communication delays.
• Food, medicine, equipment, and medical supplies need to be packed for multi-year trips without resupply.
• Medical training prepares astronauts to respond to health problems.
• Astronauts learn to produce intravenous (IV) solutions using onboard equipment and purified water.
• Crew members perform ultrasound scans on each other to monitor organ health.
• Diagnostic testing and treatment protocols are in place for crew members who become sick.
• NASA studies and improves food formulation, processing, packaging, and preservation systems.
• Space-resilient medications and packaging systems are essential for long-duration missions.

Hostile/Closed Environments

• The ecosystem inside spacecraft significantly impacts astronaut life.
• Microbes can change in space, and microorganisms transfer more easily between people in closed habitats.
• Air quality is monitored in the space station to ensure a breathable atmosphere.
• Thermal Control Systems maintain temperatures.
• Astronauts receive flu shots and quarantine before missions to prevent illness.
• Crews change air filters, clean surfaces, and treat water to prevent contamination-related illnesses.
• Living and working environments are planned for comfort and efficiency.
• New LED lighting systems onboard simulate natural Earth-like lighting.

How Space Affects the Human Body

• Weaker gravity on the ISS or spacecraft affects the human body significantly.
• "Space sickness," including headaches, nausea, and vomiting, is common.
• Radiation doses are higher, increasing the risk of cataracts, DNA damage, and cancer.
• Muscles lose mass and strength.
• Bones lose density and strength; astronauts can lose up to 1.5% of their bone mass each month, compared to the typical 1% yearly loss for adults over 50.